3mm Testing in July 2001
description
Transcript of 3mm Testing in July 2001
3mm Testing in July 2001
Tony Wong
ATNF Epping
CA Forum, 6 Sep
Bandpass at 90.56 GHz
3c279128 MHz64 chans
3c279128 MHz64 chans
Bandpass at 90.68 GHz
After bandpass
calibration applied
Bandpass at 90.68 GHz
Phase/amp stability at 90 GHz
RMS 10but
amplitude variations
much greater!
Phase/amp stability at 90 GHz
Phase cycles
every 20 minutes
Phase/amp stability at 22 GHz
Amps decreasing- worsening weather?
How often to calibrate?
5 min on 3c279:
10% amp fluctuation, RMS 15
System Temperatures
Tsys, corrected for atmospheric absorption, was determined using
the paddle while stepping in frequency from 84-87
GHz.Some of the frequency variation may be due to
varying atmosphere.
System Temperatures
Same observation for 87-91 GHz.
System Temperatures
Since the “psJy” scale is derived
assuming constant GTsys of 500 Jy, the
visibility amplitude in psJy is anticorrelated
with Tsys.
Sensitivity Estimate, 86 GHz
Assuming a flux of 8 Jy for Uranus, the observed amplitude and Tsys give the geometric mean Jy/K for the two antennas.
Sensitivity Estimate, 90 GHz
Note strong RFI at 88.160 GHz. Significant RFI is also found at 88.000 and 88.320 GHz, weaker at 88.240 GHz.
Some Science ResultsMolecules in IRC+10216
HCN
HNC
C3N
SiS
Some Science ResultsDense Gas in the LMC
HCN
HCO+
Thermal SiO in N6334
W 17.5”
center